#include "internal.h"
/*
- * By default transparent hugepage support is enabled for all mappings
- * and khugepaged scans all mappings. Defrag is only invoked by
- * khugepaged hugepage allocations and by page faults inside
- * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived
- * allocations.
+ * By default transparent hugepage support is disabled in order that avoid
+ * to risk increase the memory footprint of applications without a guaranteed
+ * benefit. When transparent hugepage support is enabled, is for all mappings,
+ * and khugepaged scans all mappings.
+ * Defrag is invoked by khugepaged hugepage allocations and by page faults
+ * for all hugepage allocations.
*/
unsigned long transparent_hugepage_flags __read_mostly =
#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
pgtable_trans_huge_deposit(mm, pmd, pgtable);
set_pmd_at(mm, haddr, pmd, entry);
add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
- mm->nr_ptes++;
+ atomic_long_inc(&mm->nr_ptes);
spin_unlock(&mm->page_table_lock);
}
HPAGE_PMD_ORDER, vma, haddr, nd);
}
-#ifndef CONFIG_NUMA
-static inline struct page *alloc_hugepage(int defrag)
-{
- return alloc_pages(alloc_hugepage_gfpmask(defrag, 0),
- HPAGE_PMD_ORDER);
-}
-#endif
-
static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
struct page *zero_page)
entry = pmd_mkhuge(entry);
pgtable_trans_huge_deposit(mm, pmd, pgtable);
set_pmd_at(mm, haddr, pmd, entry);
- mm->nr_ptes++;
+ atomic_long_inc(&mm->nr_ptes);
return true;
}
pmd = pmd_mkold(pmd_wrprotect(pmd));
pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
set_pmd_at(dst_mm, addr, dst_pmd, pmd);
- dst_mm->nr_ptes++;
+ atomic_long_inc(&dst_mm->nr_ptes);
ret = 0;
out_unlock:
struct page *page;
unsigned long haddr = addr & HPAGE_PMD_MASK;
int page_nid = -1, this_nid = numa_node_id();
- int target_nid;
+ int target_nid, last_cpupid = -1;
bool page_locked;
bool migrated = false;
+ int flags = 0;
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_same(pmd, *pmdp)))
goto out_unlock;
page = pmd_page(pmd);
+ BUG_ON(is_huge_zero_page(page));
page_nid = page_to_nid(page);
+ last_cpupid = page_cpupid_last(page);
count_vm_numa_event(NUMA_HINT_FAULTS);
- if (page_nid == this_nid)
+ if (page_nid == this_nid) {
count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
+ flags |= TNF_FAULT_LOCAL;
+ }
+
+ /*
+ * Avoid grouping on DSO/COW pages in specific and RO pages
+ * in general, RO pages shouldn't hurt as much anyway since
+ * they can be in shared cache state.
+ */
+ if (!pmd_write(pmd))
+ flags |= TNF_NO_GROUP;
/*
* Acquire the page lock to serialise THP migrations but avoid dropping
lock_page(page);
anon_vma = page_lock_anon_vma_read(page);
- /* Confirm the PTE did not while locked */
+ /* Confirm the PMD did not change while page_table_lock was released */
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_same(pmd, *pmdp))) {
unlock_page(page);
spin_unlock(&mm->page_table_lock);
migrated = migrate_misplaced_transhuge_page(mm, vma,
pmdp, pmd, addr, page, target_nid);
- if (migrated)
+ if (migrated) {
+ flags |= TNF_MIGRATED;
page_nid = target_nid;
+ }
goto out;
clear_pmdnuma:
page_unlock_anon_vma_read(anon_vma);
if (page_nid != -1)
- task_numa_fault(page_nid, HPAGE_PMD_NR, migrated);
+ task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags);
return 0;
}
int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
pmd_t *pmd, unsigned long addr)
{
+ spinlock_t *ptl;
int ret = 0;
- if (__pmd_trans_huge_lock(pmd, vma) == 1) {
+ if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
struct page *page;
pgtable_t pgtable;
pmd_t orig_pmd;
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
if (is_huge_zero_pmd(orig_pmd)) {
- tlb->mm->nr_ptes--;
- spin_unlock(&tlb->mm->page_table_lock);
+ atomic_long_dec(&tlb->mm->nr_ptes);
+ spin_unlock(ptl);
put_huge_zero_page();
} else {
page = pmd_page(orig_pmd);
VM_BUG_ON(page_mapcount(page) < 0);
add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
VM_BUG_ON(!PageHead(page));
- tlb->mm->nr_ptes--;
- spin_unlock(&tlb->mm->page_table_lock);
+ atomic_long_dec(&tlb->mm->nr_ptes);
+ spin_unlock(ptl);
tlb_remove_page(tlb, page);
}
pte_free(tlb->mm, pgtable);
unsigned long addr, unsigned long end,
unsigned char *vec)
{
+ spinlock_t *ptl;
int ret = 0;
- if (__pmd_trans_huge_lock(pmd, vma) == 1) {
+ if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
/*
* All logical pages in the range are present
* if backed by a huge page.
*/
- spin_unlock(&vma->vm_mm->page_table_lock);
+ spin_unlock(ptl);
memset(vec, 1, (end - addr) >> PAGE_SHIFT);
ret = 1;
}
unsigned long new_addr, unsigned long old_end,
pmd_t *old_pmd, pmd_t *new_pmd)
{
+ spinlock_t *old_ptl, *new_ptl;
int ret = 0;
pmd_t pmd;
goto out;
}
- ret = __pmd_trans_huge_lock(old_pmd, vma);
+ /*
+ * We don't have to worry about the ordering of src and dst
+ * ptlocks because exclusive mmap_sem prevents deadlock.
+ */
+ ret = __pmd_trans_huge_lock(old_pmd, vma, &old_ptl);
if (ret == 1) {
+ new_ptl = pmd_lockptr(mm, new_pmd);
+ if (new_ptl != old_ptl)
+ spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
VM_BUG_ON(!pmd_none(*new_pmd));
set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd));
- spin_unlock(&mm->page_table_lock);
+ if (new_ptl != old_ptl)
+ spin_unlock(new_ptl);
+ spin_unlock(old_ptl);
}
out:
return ret;
}
+/*
+ * Returns
+ * - 0 if PMD could not be locked
+ * - 1 if PMD was locked but protections unchange and TLB flush unnecessary
+ * - HPAGE_PMD_NR is protections changed and TLB flush necessary
+ */
int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, pgprot_t newprot, int prot_numa)
{
struct mm_struct *mm = vma->vm_mm;
+ spinlock_t *ptl;
int ret = 0;
- if (__pmd_trans_huge_lock(pmd, vma) == 1) {
+ if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
pmd_t entry;
- entry = pmdp_get_and_clear(mm, addr, pmd);
+ ret = 1;
if (!prot_numa) {
+ entry = pmdp_get_and_clear(mm, addr, pmd);
entry = pmd_modify(entry, newprot);
+ ret = HPAGE_PMD_NR;
BUG_ON(pmd_write(entry));
} else {
struct page *page = pmd_page(*pmd);
- /* only check non-shared pages */
- if (page_mapcount(page) == 1 &&
+ /*
+ * Do not trap faults against the zero page. The
+ * read-only data is likely to be read-cached on the
+ * local CPU cache and it is less useful to know about
+ * local vs remote hits on the zero page.
+ */
+ if (!is_huge_zero_page(page) &&
!pmd_numa(*pmd)) {
+ entry = pmdp_get_and_clear(mm, addr, pmd);
entry = pmd_mknuma(entry);
+ ret = HPAGE_PMD_NR;
}
}
- set_pmd_at(mm, addr, pmd, entry);
- spin_unlock(&vma->vm_mm->page_table_lock);
- ret = 1;
+
+ /* Set PMD if cleared earlier */
+ if (ret == HPAGE_PMD_NR)
+ set_pmd_at(mm, addr, pmd, entry);
+
+ spin_unlock(ptl);
}
return ret;
* Note that if it returns 1, this routine returns without unlocking page
* table locks. So callers must unlock them.
*/
-int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
+int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
+ spinlock_t **ptl)
{
- spin_lock(&vma->vm_mm->page_table_lock);
+ *ptl = pmd_lock(vma->vm_mm, pmd);
if (likely(pmd_trans_huge(*pmd))) {
if (unlikely(pmd_trans_splitting(*pmd))) {
- spin_unlock(&vma->vm_mm->page_table_lock);
+ spin_unlock(*ptl);
wait_split_huge_page(vma->anon_vma, pmd);
return -1;
} else {
return 1;
}
}
- spin_unlock(&vma->vm_mm->page_table_lock);
+ spin_unlock(*ptl);
return 0;
}
+/*
+ * This function returns whether a given @page is mapped onto the @address
+ * in the virtual space of @mm.
+ *
+ * When it's true, this function returns *pmd with holding the page table lock
+ * and passing it back to the caller via @ptl.
+ * If it's false, returns NULL without holding the page table lock.
+ */
pmd_t *page_check_address_pmd(struct page *page,
struct mm_struct *mm,
unsigned long address,
- enum page_check_address_pmd_flag flag)
+ enum page_check_address_pmd_flag flag,
+ spinlock_t **ptl)
{
- pmd_t *pmd, *ret = NULL;
+ pmd_t *pmd;
if (address & ~HPAGE_PMD_MASK)
- goto out;
+ return NULL;
pmd = mm_find_pmd(mm, address);
if (!pmd)
- goto out;
+ return NULL;
+ *ptl = pmd_lock(mm, pmd);
if (pmd_none(*pmd))
- goto out;
+ goto unlock;
if (pmd_page(*pmd) != page)
- goto out;
+ goto unlock;
/*
* split_vma() may create temporary aliased mappings. There is
* no risk as long as all huge pmd are found and have their
*/
if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG &&
pmd_trans_splitting(*pmd))
- goto out;
+ goto unlock;
if (pmd_trans_huge(*pmd)) {
VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG &&
!pmd_trans_splitting(*pmd));
- ret = pmd;
+ return pmd;
}
-out:
- return ret;
+unlock:
+ spin_unlock(*ptl);
+ return NULL;
}
static int __split_huge_page_splitting(struct page *page,
unsigned long address)
{
struct mm_struct *mm = vma->vm_mm;
+ spinlock_t *ptl;
pmd_t *pmd;
int ret = 0;
/* For mmu_notifiers */
const unsigned long mmun_end = address + HPAGE_PMD_SIZE;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
- spin_lock(&mm->page_table_lock);
pmd = page_check_address_pmd(page, mm, address,
- PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG);
+ PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl);
if (pmd) {
/*
* We can't temporarily set the pmd to null in order
*/
pmdp_splitting_flush(vma, address, pmd);
ret = 1;
+ spin_unlock(ptl);
}
- spin_unlock(&mm->page_table_lock);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
return ret;
page_tail->mapping = page->mapping;
page_tail->index = page->index + i;
- page_nid_xchg_last(page_tail, page_nid_last(page));
+ page_cpupid_xchg_last(page_tail, page_cpupid_last(page));
BUG_ON(!PageAnon(page_tail));
BUG_ON(!PageUptodate(page_tail));
unsigned long address)
{
struct mm_struct *mm = vma->vm_mm;
+ spinlock_t *ptl;
pmd_t *pmd, _pmd;
int ret = 0, i;
pgtable_t pgtable;
unsigned long haddr;
- spin_lock(&mm->page_table_lock);
pmd = page_check_address_pmd(page, mm, address,
- PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG);
+ PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG, &ptl);
if (pmd) {
pgtable = pgtable_trans_huge_withdraw(mm, pmd);
pmd_populate(mm, &_pmd, pgtable);
pmdp_invalidate(vma, address, pmd);
pmd_populate(mm, pmd, pgtable);
ret = 1;
+ spin_unlock(ptl);
}
- spin_unlock(&mm->page_table_lock);
return ret;
}
msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
}
+static int khugepaged_node_load[MAX_NUMNODES];
+
#ifdef CONFIG_NUMA
+static int khugepaged_find_target_node(void)
+{
+ static int last_khugepaged_target_node = NUMA_NO_NODE;
+ int nid, target_node = 0, max_value = 0;
+
+ /* find first node with max normal pages hit */
+ for (nid = 0; nid < MAX_NUMNODES; nid++)
+ if (khugepaged_node_load[nid] > max_value) {
+ max_value = khugepaged_node_load[nid];
+ target_node = nid;
+ }
+
+ /* do some balance if several nodes have the same hit record */
+ if (target_node <= last_khugepaged_target_node)
+ for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES;
+ nid++)
+ if (max_value == khugepaged_node_load[nid]) {
+ target_node = nid;
+ break;
+ }
+
+ last_khugepaged_target_node = target_node;
+ return target_node;
+}
+
static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
{
if (IS_ERR(*hpage)) {
* mmap_sem in read mode is good idea also to allow greater
* scalability.
*/
- *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address,
- node, __GFP_OTHER_NODE);
-
+ *hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask(
+ khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER);
/*
* After allocating the hugepage, release the mmap_sem read lock in
* preparation for taking it in write mode.
return *hpage;
}
#else
+static int khugepaged_find_target_node(void)
+{
+ return 0;
+}
+
+static inline struct page *alloc_hugepage(int defrag)
+{
+ return alloc_pages(alloc_hugepage_gfpmask(defrag, 0),
+ HPAGE_PMD_ORDER);
+}
+
static struct page *khugepaged_alloc_hugepage(bool *wait)
{
struct page *hpage;
if (pmd_trans_huge(*pmd))
goto out;
+ memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR;
_pte++, _address += PAGE_SIZE) {
if (unlikely(!page))
goto out_unmap;
/*
- * Chose the node of the first page. This could
- * be more sophisticated and look at more pages,
- * but isn't for now.
+ * Record which node the original page is from and save this
+ * information to khugepaged_node_load[].
+ * Khupaged will allocate hugepage from the node has the max
+ * hit record.
*/
- if (node == NUMA_NO_NODE)
- node = page_to_nid(page);
+ node = page_to_nid(page);
+ khugepaged_node_load[node]++;
VM_BUG_ON(PageCompound(page));
if (!PageLRU(page) || PageLocked(page) || !PageAnon(page))
goto out_unmap;
ret = 1;
out_unmap:
pte_unmap_unlock(pte, ptl);
- if (ret)
+ if (ret) {
+ node = khugepaged_find_target_node();
/* collapse_huge_page will return with the mmap_sem released */
collapse_huge_page(mm, address, hpage, vma, node);
+ }
out:
return ret;
}
projects / cascardo / linux.git / blobdiff